Such an electric lamp is known from British Patent Application No. GB 2 093 632 A and can be used as a vehicle headlamp. The lamp may be constructed, for example, as an H-1 lamp and have an incandescent body arranged in the direction of the sleeve inside the lamp vessel in a halogen-containing gas.
The insulator body of the known lamp has a hole in a side face between the end faces, which hole runs on to the opposing side face and into which the sleeve enters with an inward projection so as to fix the insulator body in the sleeve.
Since the formation of such a hole necessitates a more expensive, multiple mould for the manufacture of the insulator body, it is more attractive in the case of an insulator body made of synthetic resin to provide the hole therein by drilling after the manufacture of the body. The use of synthetic resin, however, involves a risk, i.e. when the lamp is used in an optical system, for example a reflector, volatile components originating from the resin may be deposited in that system and pollute it. This is why a ceramic insulator body is preferred.
A disadvantage of the ceramic insulator body of the known lamp is that a multiple mould is necessary for manufacturing the insulator body. This is because it is not possible to provide a hole in a formed ceramic body in an industrially attractive manner afterwards.